Device for salvaging metal objects and salvaging method

ABSTRACT

A submersible device for use in salvaging metal objects comprises a magnetized metallic housing containing compressed thermit suitably sealed from the water. The housing in lowered on cables until its magnetic field causes contact with the object to be salvaged. The thermit may be ignited by a voltage applied to a wire which is returned to the vessel from which the housing is deployed. When the thermit ignites, it produces a molten metal which burns through the bottom of the housing and forms a weld between the housing wall and the surface of the metal object to be salvaged. The object may then be raised by pulling on the cables supporting the housing.

Andersen [451 Mar. is, 1975 1 DEVICE FOR SALVAGING METAL OBJECTS AND SALVAGING METHOD [76] Inventor: Leonard Morgansen Andersen, 46

Alexander Ave., Yonkers, NY.

221 Filed: June 20,1973 211 Appl. No.: 371,875

[52] U.S. Cl. 114/51 [51] Int. Cl. B63c 7/04 [58] Field of Search 114/51, 206 A; 75/27, 44 SC,

3/1966 Jennings 294/861 X 3,421,570 1/1969 Guntermann 75/27 3,711,019 l/l973 Rulo 228/56 Primary Examiner-George E. A. Halvosa Assistant Examiner-Gregory W. OConnor [57] ABSTRACT A submersible device for use in salvaging metal objects comprises a magnetized metallic housing containing compressed thermit suitably sealed from the water. The housing in lowered on cables until its magnetic field causes contact with the object to be salvaged. The thermit may be ignited by a voltage applied to a wire which is returned to the vessel from which the housing is deployed. When the thermit ignites, it produces a molten metal which burns through the bottom of the housing and forms a weld between the housing wall and the surface of the metal object to be salvaged. The object may then be raised by pulling on the cables supporting the housing.

6 Claims, 7 Drawing Figures [56] References Cited UNITED STATES PATENTS 1,168,061 1/1916 Deppeler 104/15 2,154,654 4/1939 Armentrout et al...... 294/861 2,253,364 8/1941 Cohen ..75/27 2,374,134 4/1945 Richard ll4/51 2,717,204 9/1955 Noddin et a1.. 75/27 2,789,004 4/1957 Foster ..294/86.1

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DEVICE FOR SALVAGING METAL OBJECTS AND SALVAGING METHOD This invention relates to a device for use in salvaging metal objects and to a method of salvaging such objects.

The salvaging of underwater objects is an expensive and complex undertaking. With most known techniques, a diver must secure grappling means to the object to be salvaged so that it can be raised to the surface. In the case of large boats, this is frequently impractical and various other techniques have been devised for their recovery. For example, certain plastic materials may be pumped into the hull of a boat and activated to provide a cellular mass which will tend to raise the object to the surface of the water because of the foams displacement of water. However, this is an expensive process which also requires the services of divers and in many cases such processes are not economically feasible.

U.S. Pat. No. 3,385,250 of Raule discloses a submersible salvaging device which is magnetically attracted to a ferrous object and, thereafter, capable of securing itself to the object by drilling and tapping a hole. However, this device also is relatively expensive and, therefore, commercially impractical in situations where a large number of such devices must be used because of the bulk of the object to be salvaged.

The present invention provides a relatively inexpensive device for use in salvaging submerged metallic objects. It is a highly portable device which, in most cases, may be secured to the surface of the object to be salvaged without diver assistance in a way which is completely different from known devices of this type. Furthermore, the device may be quickly and easily deployed and secured, and requires very little on board support equipment for its use. The invention is not only commercially practicable, it is of particular advantage where time is important.

In accordance with the invention, a compressed ignitable powder, such as thermit, is contained in a housing which may be magnetized and lowered into the water by means of cables. In the case of an object made of a ferrous or other magnetic material, the housing will be attracted to the object and when contact is made, the thermit is ignited by means of a voltage applied to suitable electric leads which extend through the housing into the thermit. Ignition ofthe thermit produces a molten metal having a temperature close to 2388C which burns through the bottom of the housing and the surface of the metal object to fuse the remaining portion of the housing to the metal object. After the required number of devices have been deployed and activated (depending on the size of the object) the object may be raised to the surface by pulling on the cables or by other lifting means which can be secured to the housing.

The invention is described in further detail below with reference to the attached drawings wherein:

FIG. I is a side sectional view of a preferred embodiment of the invention;

FIGS. 2A and 2B are side sectional views similar to FIG. 1 diagrammatically illustrating the weld formed between the housing and surface of the metallic object to be salvaged;

FIG. 3 is a side sectional view of a second embodiment of the invention; and

FIGS. 4A, 4B and 4C diagrammatically illustrate the method of using the device illustrated in FIG. 3.

FIG. 1 shows a surface of the object to be salvaged at 8. The device, according to the invention, includes a cylindrical housing 10 made of steel and open on the top. Housing 10 includes a curved rounded bottom surface 12 extending into a flange 13. The housing contains a thermit material 14 which has been compressed to about 8000 psi and a layer of similarly compressed flux material 16 enveloping the thermit 14. When compressed to this extent, the thermit and flux materials become solid, brick-like masses. A thin steel cylinder 17 separates the thermit 14 and flux 16, and helps to disperse the heat of reaction to reduce hot spots. An igniting powder 18 is placed above the thermit 14.

The thermit mixture 14 is a mixture of iron oxide and aluminum particles (commercially available as plain thermit) and has known uses in welding processes. If an oxidation reaction is started (referred to as igniting), the aluminum, which is a strong reducing agent, combines with the oxygen from the iron oxide and reduces the iron oxide to iron. The intense heat that results, be-

cause of the chemical action, not only melts the iron but raises it to a temperature of 2388C. Consequently, the material may be used to fuse with other metal surfaces to form a strong weld.

The igniting powder 18 may consist of a lightly compressed mixture of fine particle aluminum powder and fine particle iron oxide (Fe O in proportion by weight of 3 to 7. The particle size will depend on the available current. For example, with only a twelve volt battery, the finest commercially available particle size would be used. Light compression (less than 25 psi) is necessary to prevent gapping through the mixture and to facilitate reaction. This preferred igniting powder is also a thermit mixture and is preferred to other igniting powders because it does not emit gases. The flux 16 which surrounds the thermit mixture 14, may comprise known materials such as, for example, high cellulose welding rod coating or H-700 submerged arc welding flux sold by Hobart Brothers Company of Troy, Ohio. This flux material aids in controlling the flow of the molten iron, insulates the molten iron from the water, and further anneals the weld between the housing and surface 8.

A pair of ignition wires 20 (shown diagrammatically in FIG. I) extend into the igniting powder 18. The ignition wire is standard and may include a bare nickelchromium wire (not specifically illustrated) which, when a voltage is applied to the wires 20, will be heated to a temperature sufficient to ignite the igniting powder 18 and, consequently, the thermit mixture 14. A watertight seal is formed by a cap 22 which may be made of thin steel and is press-fit onto the open end of housing 10 with the insulated ignition wires 20 pressed between the cap 22 and the interior surface of housing 10.

The upper portion of the housing 10 and the seal 22 may include two pairs of openings 24 and 26 (only one opening 26 being illustrated) through which pairs of cables 28 and 30 pass. These cables 28 and 30 are used to raise and lower the device and may be any suitable cable depending upon the application. The cables are secured at a couplingjoint 32 which may be grasped by a suitable device on the vessel from which the devices are to be deployed.

The particular arrangement for lowering and raising the device is not a part of this invention, the cable arrangement in FIG. 1 being selected principally for purposes of economy. Since the device frequently will not be welded to a submerged object with its longitudinal axis vertical, the cables 28 and 30 should be capable of sliding within the coupling joint 32 so that equal forces will be applied to the four attachment points on the housing (openings 24 and 26) regardless of the angle of the device after welding.

The entire device as so far described is enclosed within a metal cover 36, the bottom of which rests on flange 13. Again, for purposes of economy, the cables 28 and 30 may be brought from openings 24 and 26 down to the bottom of the cover 36. The bottom of the cover 36 may be adhesively secured to flange 13 to form a watertight seal between the cover and flange and creating an air space enveloping the housing 10. An annular counterweight 38 may be secured to cover 36 to help maintain the seal between cover 36 and flange 13 as the device is deployed into the water, and to hold the cover down during welding when the adhesive seal will burn off.

A copper ring 40 may be secured (eg by an epoxy adhesive) to the bottom of flange 13. Ring 40 retains the molten metal because of its excellent heat conductive properties so as to prevent the liquid iron from running off surface 8.

After the weld has been formed (as described below) and the cables 28 and 30 are pulled, the cover 36 will be dislodged but this is of no particular consequence. By running the cables 28 and 30 beneath the cover 36, it is not necessary to provide additional watertight openings in the cover.

The device also includes an annular ring 40 which may be made of copper and is secured to the undersurface of flange 14 for the purpose of directing the molten metal against the surface of the metal object to be salvaged.

The manner in which the embodiment of FIG. 1 is used should be apparent from the foregoing description. Preferably, the device is magnetized by subjecting its ferrous components to a strong magnetic field so that it may be deployed into the water by means of cables 28 and 30 and allowed to attach itself magnetically to the ferrous surface of the object 8. After the housing is in position, a voltage is applied to the ignition wires 20 and the powder 18 is ignited by the heat created by the nickel chromium wire within the powder. Ignition of powder 18 ignites the thermit mixture 14 creating, as described above, a molten bath of iron at a temperature of 2388C. This molten material melts the bottom surface 12 of the housing and also burns through the contiguous surface of object 8. The extreme temperatures fuse the housing 10 to the surface 8 to form an extremely strong junction as shown in FIG. 2A. For example, it is estimated that in the case ofa housing of about 6 inches in outer diameter, the weld formed would be capable of lifting a total weight of about 5 tons. The entire welding process requires only about 30 seconds.

In virtually all cases, a number of devices will have to be secured to the object to be salvaged. After all of the required devices have been welded in place, the cables 28 and 30 of the device are pulled to raise the object to the surface as diagrammatically shown in FIG. 2B.

FIG. 3 illustrates a second embodiment of the invention. In this embodiment, the arrangement of the housing '10, thermit 14, flux l6, igniting powder 18 and seal 22 is essentially the same as that of the embodiment illustrated in FIG. 1. The cables 28 and 30 are arranged slightly differently, as shown, but this is not material.

In accordance with this embodiment of the invention, a large block 50 of non-metallic material such as plastic or wood is press-fit into the covering seal 22. A first explosive device 52 is suitably secured to the bottom of housing surface 12 and a second explosive device 54 is suitably secured to a plate 56 attached to the top of block 50. If desired to provide an insulating air space, the entire device may be enclosed within a cover such as the cover 36 illustrated in FIG. 1.

The purpose of the explosive device 52 is to clean the surface to be welded where, because of an extended period of submersion or other causes, the metal object does not include a surface to which a satisfactory weld can be formed. The purpose of the explosive device 54 is to drive the housing surface 12 into the metal surface of the object to be salvaged to create a slight indentation which will tend to retain the molten metal from the thermit mixture. The explosive charges 52 and 54 may include ignition wires 56 and 58 which extend to the vessel from which the device is deployed along with the wires 20 for the igniting powder 18. In this way, the explosive charges 52 and 54 can be activated from the deploying vessel although the invention contemplates any type of control for these devices.

FIGS. 4A, 4B and 4C show the manner in which the embodiment of FIG. 3 is used to form a tight weld to a metal surface 8 containing barnacles or some other material 60 which would normally interfere with the weld. Thus, in FIG. 4A, when the device makes contact with the material 60, the explosive charge 52 will clean a small area allowing the housing surface 12 to contact the metal surface 8. When the device is returned to surface 8, the explosive charge 54 drives the entire device against the metal surface 8 with sufficient force to make a slight indentation. Thereafter, the thermit mixture 14 is ignited as described above, the housing 10 fused to surface 8, and the device hauled to the surface of the water by means of the cables 28 and 30.

In the embodiment of FIG. 3, the non-metal block 50 absorbs the shock of the explosive device 54 and also tends to maintain the device in a vertical position. Of course, if necessary, the device may be suitably weighted to counteract the buoyancy of block 50.

If the device is used to salvage vessels containing fluids and, particularly, oil, there is a possibility that after the weld is formed the oil will leak from the vessel through the housing which may no longer be fluid-tight after the thermit mixture 14 has been ignited. Hence, in such a situation, the entire device may be covered with an inverted can having a urethane foam seal and a magnet for securing the can to the tankers surface. In the event of leakage, the oil will be confined to the space within the inverted can.

The specific construction of the embodiments illustrated have been selected with a view toward economy since the devices are expendable. Accordingly, numerous structural changes may be made. Instead of lowering the device by means of cables 28 and 30 which are used to haul the submerged object to the surface, the housing may contain some type of attachment means to which a heavy hauling line can be coupled after the weld is formed. Special attachment lugs or ears may be formed on housing 10, but the illustrated construction has proved workable and is presently preferred for purposes ofeconomy. Selection of materials (including the thermit) and the size of the device itself will depend on the applications involved. Typically, housing may have an outer diameter of 6 inches and be filled with about pounds of thermit 14. Approximately three to four pounds of flux 16 are used forming a cylindrical layer about one-fourth three-eighths inches thick. About 5 pounds of the thermit igniting powder 18 may be used. The thickness of the housing walls is about three-eighths inches. With respect to the embodiment of FIGS. 3 and 4, explosive charge 52 may comprise a No. 6 electrical cap with instant detonation and two grams PETN explosive (from DuPont). Charge 54 may comprise a No. 6 electrical cap with ms delay detonation and four grams PETN.

What is claimed is:

1. A submersible device for use in salvaging metal objects from a body of water, comprising a housing having an opening at one end;

a compressed thermit mixture within said housing,

said thermit mixture being enveloped by a flux material;

a metal container enveloping said housing to form an insulating air space between the interior surface of said container and said housing, with means forming a watertight seal between said container and said housing;

an igniting powder above the thermit mixture within said housing, said igniting powder being of the type which does not emit gases upon ignition;

means for igniting said igniting powder;

means for sealing the open end of said housing;

means enveloping the closed end of said housing for directing the flow of molten metal after said thermit mixture has been ignited toward a confined area of an object to be salvaged; and

lifting means connected to said housing for enabling said housing to be pulled toward the surface of the water after it has been welded to a metal object by ignition of said thermit.

2. A submersible device according to claim 1, wherein said thermit mixture is compressed to the form of a solid brickJike mass.

3. A submersible device according to claim 2, wherein said thermit mixture and said flux material are compressed to about 8000 psi.

4. A submersible device according to claim 2, wherein said igniting power is a second thermit mixture of finer particle size and under less compression than said first named thermit mixture, and wherein said igniting means comprises an ignition wire within said second thermit mixture.

5. A submersible device according to claim 4, wherein the closed end of said housing is rounded and wherein said means enveloping the closed end of said housing comprises an annular metallic ring.

6. A submersible device according to claim 1,

wherein said housing is magnetized. 

1. A submersible device for use in salvaging metal objects from a body of water, comprising a housing having an opening at one end; a compressed thermit mixture within said housing, said thermit mixture being enveloped by a flux material; a metal container enveloping said housing to form an insulating air space between the interior surface of said container and said housing, with means forming a watertight seal between said container and said housing; an igniting powder above the thermit mixture within said housing, said igniting powder being of the type which does not emit gases upon ignition; means for igniting said igniting powder; means for sealing the open end of said housing; means enveloping the closed end of said housing for directing the flow of molten metal after said thermit mixture has been ignited toward a confined area of an object to be salvaged; and lifting means connected to said housing for enabling said housing to be pulled toward the surface of the water after it has been welded to a metal object by ignition of said thermit.
 2. A submersible device according to claim 1, wherein said thermit mixture is compressed to the form of a solid brick-like mass.
 3. A submersible device according to claim 2, wherein said thermit mixture and said flux material are compressed to about 8000 psi.
 4. A submersible device according to claim 2, wherein said igniting power is a second thermit mixture of finer particle size and under less compression than said first named thermit mixture, and wherein said igniting means comprises an ignition wire within said second thermit mixture.
 5. A submersible device according to claim 4, wherein the closed end of said housing is rounded and wherein said means enveloping the closed end of said housing comprises an annular metallic ring.
 6. A submersible device according to claim 1, wherein said housing is magnetized. 